Let’s create the producer application by pasting the following Go code into a file named producer.go. 
package main

import (
	"context"
	"fmt"
	"math/rand"
	"os"

	"github.com/apache/pulsar-client-go/pulsar"
)

func main() {

	client, err := pulsar.NewClient(pulsar.ClientOptions{
		URL:            "<Broker Service URL>",
		Authentication: pulsar.NewAuthenticationToken("<API KEY>"),
	})

	if err != nil {
		fmt.Printf("Failed to create Pulsar client: %s", err)
		os.Exit(1)
	}

	users := [...]string{"eabara", "jsmith", "sgarcia", "jbernard", "htanaka", "awalther"}
	items := [...]string{"book", "alarm clock", "t-shirts", "gift card", "batteries"}
	topic := "purchases"

	producer, err := client.CreateProducer(pulsar.ProducerOptions{
		Topic: topic,
	})

	if err != nil {
		fmt.Printf("Failed to create Pulsar producer: %s", err)
		os.Exit(1)
	}

	defer producer.Close()

	for n := 0; n < 10; n++ {
		key := users[rand.Intn(len(users))]
		data := items[rand.Intn(len(items))]
		if msgId, err := producer.Send(context.Background(), &pulsar.ProducerMessage{
			Key:     key,
			Payload: []byte(data),
		}); err != nil {
			fmt.Printf("Failed to deliver message: %s", err)
		} else {
			fmt.Printf("Produced event to topic: ID = %s, key = %-10s value = %s\n", msgId, key, data)
		}
	}
}
Fill in the appropriate <Broker Service URL> endpoint and <API KEY> in the URL and Authentication properties where the producer is instantiated using the pulsar.NewClient method. Compile the producer with the following: 
go build -o out/producer producer.go
If you get any errors during the build make sure that you initialized the module correctly per the instructions in the previous step.